铸造砂柜的传热.doc
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铸造砂柜的传热,摘要在铸造行业中，型砂性能对铸件的质量和废品率有一定影响，型砂性能主要是指型砂的温度、强度、紧实率和水分等。其中，型砂温度对铸造的影响较大，型砂温度过高对铸造带来很多危害。本文基于对热砂在储砂柜中冷却的传热过程理论分析，结合强化传热方法，研究旧砂冷却循环过程中型砂置于储砂柜中的冷却过程，寻求合理的冷却方式和储砂柜结构形...
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摘 要
在铸造行业中，型砂性能对铸件的质量和废品率有一定影响，型砂性能主要是指型砂的温度、强度、紧实率和水分等。其中，型砂温度对铸造的影响较大，型砂温度过高对铸造带来很多危害。本文基于对热砂在储砂柜中冷却的传热过程理论分析，结合强化传热方法，研究旧砂冷却循环过程中型砂置于储砂柜中的冷却过程，寻求合理的冷却方式和储砂柜结构形式。
本文采用以下几种强化冷却手段进行模拟分析：⑴储砂柜外表面加针肋；⑵储砂柜外加套筒；⑶改变针肋排列方式；⑷采用热管强化；⑸结合针肋与套筒；⑹在套筒进风口加风机。前两种方式是对储砂柜进行初步试验模拟分析，后四种方式是对储砂柜模型的优化，以寻找一种更合理的强化冷却措施。
对储砂柜的传热数值模拟是本文的主要研究手段，通过有限元分析软件建立不同的三维储砂柜模型并进行气-固耦合数值模拟。对模拟结果分析得出，最终时刻热型砂内最高温度值及时间-温度曲线，从而判断不同方式的冷却效果。
研究结果表明：外加套筒的储砂柜结构对型砂的冷却较明显，而且制造成本低；热管强化的储砂柜结构对型砂的冷却效果更明显，但制造成本较高。
本文依据相似理论还针对两种简单砂柜模型进行了实验方案设计，建立相似模型，确定实验及数据整理方法，为后续实验研究提供理论依据。
关键词：储砂柜；强化传热；数值模拟；相似理论
Abstract
In the foundry industry, the performance of sand has a great impact on the quality and defective index of casting. The performance of sand mainly refers to its temperature, intensity, compactability and moisture. Among them, the sand temperature has the greatest impact on the casting. High temperature of sand can bring lots of harm to casting. The paper is to find a model of sand that is suitable for cooling sand, combining with enhanced heat transfer method, based on the theoretical analysis of heat transfer process of sand cabinet.
This paper is based on the casting sand cooling related knowledge，from the casting sand cooling heat transfer principle，firstly simulate natural cooling heat transfer effect of sand cabinet，then looking for some reasonable cooling system. Through the contrast analysis, explain the selected cooling methods in theory. We can reach the highest temperature inside of sand and time-temperature in order to determine the effect of cooling. Establish similar model of sand cabinet then sort out the experiment data according to similarity theory, which provides a theoretical basis for latter experimental analysis.
In this paper, the following method of enhanced heat transfer is mentioned in the simulation analysis: (1) Needle rib added on the outer surface of the sand storage cabinet. (2) Sleeve added on the outer of the sand storage cabinet. (3) Changed arrangement of needle rib. (4) Using the heat pipe. (5) Combining sleeve with needle rib. (6) Adding fans to inlet of the sleeve. The first two methods above are used to have the preliminary test simulation analysis, and the latter four methods are to optimize the model of sand storage cabinet, which is to find a more reasonable measure of cooling sand temperature.
The focus of this study is on the numerical simulation of heat transfer. Establish a different three-dimensional model of sand storage cabinet by finite element analysis software, then carry out numerical simulation analysis of gas-solid coupling. We can reach the highest temperature inside of sand and time-temperature in order to determine the effect of cooling.
The results show that the cooling effect of the sand storage cabinet with is obvious and its cost is low; the cooling effect of the sand storage cabinet with heat pipe is more obvious but higher costs.
There is an experimental design of two simple model of sand cabinet by similarity theory in this paper. Establish similar model of sand cabinet then sort out the experiment data according to similarity theory, which provides a theoretical basis for latter experimental analysis.
Keywords: sand storage cabinet; enhanced heat transfer; numerical simulation; similarity theory.
目 录
摘 要 I
Abstract III
第1章 绪论 1
1.1 课题研究背景 1
1.2 国内、外研究现状 3
1.2.1 型热性能研究现状 3
1.2.2 型砂冷却方式研究现状 3
1.3 本课题研究的意义 5
1.4 本文研究的主要内容及方法 7
第2章 砂柜传热理论分析 9
2.1 砂柜的热分析 9
2.1.1 热分析类型的确定 9
2.1.2 热传递方式 10
2.2 耦合场的概念及作用 12
2.2.1 耦合场的概念 12
2.2.2 耦合场的作用 13
2.3 自然对流的概念及研究现状 13
2.3.1 自然对流的概念 13
2.3.2 自然对流研究与发展现状 15
2.4 强化对流换热的方式 16
2.5 本章小结 17
第3章 砂柜数学物理模型的确定 19
3.1 计算方法的选择 19
3.1.1 有限差分法 19
3.1.2 有限元法 19
3.1.3 有限体积法 20
3.1.4 有限分析法 20
3.1.5 边界元法 20
3.2 砂柜数学模型的建立 21
3.2.1 有限元分析软件简介 21
3.2.2 控制方程 23
3.2.3 流体模型 24
3.3 砂柜物理模型的建立 26
3.3.1 三维实体固体模型的建立 26
3.3.2 三维流体模型的建立 27
3.4 模型假设 28
3.5 本章小结 28
第4章 砂柜模型的数值模拟计算 29
4.1 单元类型选择 29
4.2 网格划分 29
4.2.1 固体模型网格划分 30
4.2.2 流体模型网格..
在铸造行业中，型砂性能对铸件的质量和废品率有一定影响，型砂性能主要是指型砂的温度、强度、紧实率和水分等。其中，型砂温度对铸造的影响较大，型砂温度过高对铸造带来很多危害。本文基于对热砂在储砂柜中冷却的传热过程理论分析，结合强化传热方法，研究旧砂冷却循环过程中型砂置于储砂柜中的冷却过程，寻求合理的冷却方式和储砂柜结构形式。
本文采用以下几种强化冷却手段进行模拟分析：⑴储砂柜外表面加针肋；⑵储砂柜外加套筒；⑶改变针肋排列方式；⑷采用热管强化；⑸结合针肋与套筒；⑹在套筒进风口加风机。前两种方式是对储砂柜进行初步试验模拟分析，后四种方式是对储砂柜模型的优化，以寻找一种更合理的强化冷却措施。
对储砂柜的传热数值模拟是本文的主要研究手段，通过有限元分析软件建立不同的三维储砂柜模型并进行气-固耦合数值模拟。对模拟结果分析得出，最终时刻热型砂内最高温度值及时间-温度曲线，从而判断不同方式的冷却效果。
研究结果表明：外加套筒的储砂柜结构对型砂的冷却较明显，而且制造成本低；热管强化的储砂柜结构对型砂的冷却效果更明显，但制造成本较高。
本文依据相似理论还针对两种简单砂柜模型进行了实验方案设计，建立相似模型，确定实验及数据整理方法，为后续实验研究提供理论依据。
关键词：储砂柜；强化传热；数值模拟；相似理论
Abstract
In the foundry industry, the performance of sand has a great impact on the quality and defective index of casting. The performance of sand mainly refers to its temperature, intensity, compactability and moisture. Among them, the sand temperature has the greatest impact on the casting. High temperature of sand can bring lots of harm to casting. The paper is to find a model of sand that is suitable for cooling sand, combining with enhanced heat transfer method, based on the theoretical analysis of heat transfer process of sand cabinet.
This paper is based on the casting sand cooling related knowledge，from the casting sand cooling heat transfer principle，firstly simulate natural cooling heat transfer effect of sand cabinet，then looking for some reasonable cooling system. Through the contrast analysis, explain the selected cooling methods in theory. We can reach the highest temperature inside of sand and time-temperature in order to determine the effect of cooling. Establish similar model of sand cabinet then sort out the experiment data according to similarity theory, which provides a theoretical basis for latter experimental analysis.
In this paper, the following method of enhanced heat transfer is mentioned in the simulation analysis: (1) Needle rib added on the outer surface of the sand storage cabinet. (2) Sleeve added on the outer of the sand storage cabinet. (3) Changed arrangement of needle rib. (4) Using the heat pipe. (5) Combining sleeve with needle rib. (6) Adding fans to inlet of the sleeve. The first two methods above are used to have the preliminary test simulation analysis, and the latter four methods are to optimize the model of sand storage cabinet, which is to find a more reasonable measure of cooling sand temperature.
The focus of this study is on the numerical simulation of heat transfer. Establish a different three-dimensional model of sand storage cabinet by finite element analysis software, then carry out numerical simulation analysis of gas-solid coupling. We can reach the highest temperature inside of sand and time-temperature in order to determine the effect of cooling.
The results show that the cooling effect of the sand storage cabinet with is obvious and its cost is low; the cooling effect of the sand storage cabinet with heat pipe is more obvious but higher costs.
There is an experimental design of two simple model of sand cabinet by similarity theory in this paper. Establish similar model of sand cabinet then sort out the experiment data according to similarity theory, which provides a theoretical basis for latter experimental analysis.
Keywords: sand storage cabinet; enhanced heat transfer; numerical simulation; similarity theory.
目 录
摘 要 I
Abstract III
第1章 绪论 1
1.1 课题研究背景 1
1.2 国内、外研究现状 3
1.2.1 型热性能研究现状 3
1.2.2 型砂冷却方式研究现状 3
1.3 本课题研究的意义 5
1.4 本文研究的主要内容及方法 7
第2章 砂柜传热理论分析 9
2.1 砂柜的热分析 9
2.1.1 热分析类型的确定 9
2.1.2 热传递方式 10
2.2 耦合场的概念及作用 12
2.2.1 耦合场的概念 12
2.2.2 耦合场的作用 13
2.3 自然对流的概念及研究现状 13
2.3.1 自然对流的概念 13
2.3.2 自然对流研究与发展现状 15
2.4 强化对流换热的方式 16
2.5 本章小结 17
第3章 砂柜数学物理模型的确定 19
3.1 计算方法的选择 19
3.1.1 有限差分法 19
3.1.2 有限元法 19
3.1.3 有限体积法 20
3.1.4 有限分析法 20
3.1.5 边界元法 20
3.2 砂柜数学模型的建立 21
3.2.1 有限元分析软件简介 21
3.2.2 控制方程 23
3.2.3 流体模型 24
3.3 砂柜物理模型的建立 26
3.3.1 三维实体固体模型的建立 26
3.3.2 三维流体模型的建立 27
3.4 模型假设 28
3.5 本章小结 28
第4章 砂柜模型的数值模拟计算 29
4.1 单元类型选择 29
4.2 网格划分 29
4.2.1 固体模型网格划分 30
4.2.2 流体模型网格..
